For the machining of workpieces of large longitudinal dimensions machine tools are used which have machine stands which can be moved by a motor as so-called traveling stands on a machine base which, as a rule, is flat and elongated. As a drive unit for the traveling movements of the traveling stand, mostly electric linear motors have been used lately which, in contrast to conventional electromechanical or fluidic drive systems, have advantages regarding acceleration, accuracy, costs, and the like. In such machining tools, a supporting structure is provided on the front longitudinal side of the machine base, on which can be clamped one or more of the workpieces of large longitudinal dimensions to be machined. These supporting structures are designed like bases and formed to receive workpiece tables that are stationary or can be longitudinally displaced. A considerable disadvantage of such systems is the fact that the chips accumulate in heaps on the planar surfaces of the supporting structure and the workpiece tables, respectively, and cannot be removed automatically. In addition, these known supporting structures are limited in their possibilities of variation for receiving different workpieces.